Choke system



Jan. 31, 1961 M. E- FUCHS ET AL 2,969,785

CHOKE SYSTEM Filed Jan. 5, 1959 v 4 Sheets-Sheet 1 FIG. l3.

FIG. I.

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CHOKE SYSTEM Filed Jan. 5, 1959 4 Sheets-Sheet 2 FIGZ. (II H as 1 81 23a b 9 0 o o M Q I, 5

33 I 95 4 o I 1. a O o FIGS.

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II wiul l/2'7 I l I I STARTER T E 9 F129 TO IGNITION cz I35 //3\ x29 INVEN TORS MARTIN E. FUCHS HARRY J. HERTLING ATTORNEY Jan. 31, 1961 FiledJan. 5, 1959 FIG6. 3%?

M. E. FUCHS ET AL CHOKE SYSTEM 4 Sheets-Sheet 3 {um EB 61 3 f INVENTORSMARTIN E. FUCHS 55 HARRY J. HERTLING 35 BY ATTORNEY Jan. 31, 1961 E.FUCHS ET AL 2,969,785

CHOKE SYSTEM 4 Sheets-Sheet 4 Filed Jan. 5, 1959 FIGIO.

INVENTORS i MARTIN E.FUCHS 1:1 1 BY HARRY J. HERTLING ATTORNEY CHOKESYSTEM Martin E. Fuchs and Harry J. Hertling, St. Louis, Mo., assignorsto ACE Industries, Incorporated, New York, N.Y., a corporation of NewJersey Filed Jan. 5, 1959, Ser. No. 784,972

3 Claims. (Cl. 123-179) This invention relates to choke systems forinternal combustion engines, and more particularly to an electricalchoke system for the engine of an outboard motor.

Some outboard engines are provided with an electric motor for startingthe engine, this motor being connected in a circuit including a starterswitch which may be combined with an ignition switch in a key-operatedunit, as in automotive practice, such that the key may be turned from OEposition to Start position to close both switches for starting and,after the engine has been started, returned to On position to open thestarter circuit While maintaining the ignition circuit closed. Suchoutboard engines have one or more carburetors, each provided with achoke valve. It is desirable that the choke valves of all thecarburetors be fully closed when, with the engine cold, the starterswitch is closed to start the engine, and, once the engine has beenstarted, that they be partly opened and maintained in partly openedposition until the engine has reached a predetermined operatingtemperature, and then that they be fully opened.

Accordingly, it is an object of this invention to provide a choke systemfor such an engine adapted automatically to accomplish closing of thechoke valves of the carburetors when, with the engine cold, the starterswitch is closed to start the engine, then to accomplish partial openingof the choke valves when the starter switch is opened once the enginehas started, and then to accomplish full opening of the choke valveswhen the engine has warmed up, which system is of simple and economicalconstruction and reliable in operation.

If the engine is warm but below the predetermined operating temperaturewhen the starter switch is closed, it is desirable that the choke valvesbe partly opened and maintained in partly open position until the enginereaches the predetermined operating temperature. If the engine should beabove the predetermined operating temperature when the starter switch isclosed, it is desirable that the choke valves be fully open.

Accordingly, it is a further object of this invention to provide a chokesystem adapted automatically to accomplish partial closing of the chokevalves when, with the engine warm but not up to the predeterminedoperating temperature, the starter switch is closed to start the engine,and to maintain the choke valves fully open when, with the engine at thepredetermined operating temperature, the starter switch is closed tostart the engine.

It will be understood that the invention is not limited in applicationto an outboard motor, being also useful, for example, in conjunctionwith an internal combustion engine for driving a generator in anelectric generating plant of a type wherein the engine has a startingmotor and a circuit for the starting motor including a starter switchwhich is actuated whenever there is a demand for power.

In general, a system of this invention comprises an 2,969,785 PatentedJan. 31, 1961 electrically actuated or electromagnetic means, such asasolenoid, for controlling the choke valve of the carburetor, or, wherethe engine has more than one car buretor, for controlling the chokevalves of all the carburetors. The choke valve is biased to open. Thesole noid or the like is adapted when energized to move the choke valvein closing direction. A first circuit including the starter switch and afirst engine temperature responsive switch is provided which, when boththese switches are closed, is adapted to establish suiticient voltageacross the solenoid or the like to hold the choke valve fully closedagainst the opening bias. A second circuit including a second enginetemperature responsive switch is provided for establishing a lowervoltage across the solenoid or the like sufiicient to hold the chokevalve only partly closed against the opening bias. The temperatureresponsive switches are both normally closed, the second being adaptedto open at a temperature related to the predetermined engine operatingtemperature, and the first being adapted to open at a lower temperature.With this arrangement, when the engine is cold and the starter switch isclosed to start the engine, the higher voltage is applied to thesolenoid to close the choke valve. As soon as the starter switch opens,the lower voltage is applied to the solenoid so that the choke is partlybut not fully opened. Then when the engine warms up to the predeterminedoperating temperature, the second temperature responsive switch opensand the choke valve fully opens. If the engine should be warm but belowthe predetermined operating temperature, the first temperatureresponsive switch will be open and the second closed. Accordingly, whenthe starter switch is closed, the lower voltage is applied so that thechoke is partly opened. It the engine should be at or above thepredetermined operating temperature, both temperature responsiveswitches will be open and, when the starter switch is closed, the chokewill remain fully open.

Another object of the invention is the provision of an arrangementwhereby, it the engine should not start withing a reasonable time, thechoke is fully opened for unloading purposes.

This is expeditiously accomplished by making the first temperatureresponsive switch a time delay switch, which, for example, isself-heating on flow of current therethrough, and adapted to open inresponse to flow of current through the first circuit for a prolongedperiod of time so as to accomplish opening of the choke for unloadingpurposes if the engine should fail to start.

Other objects and features will be in part apparent and in part pointedout hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated:

Fig. 1 is a perspective view of an outboard motor to which a chokesystem of this inventionis applied, the shroud for the engine of theoutboard motor being removed;

Fig. 2 is a perspective view of the upper end of the outboard motor asviewed from a difierent angle than in Fig. 1, on a larger scale thanFig. 1, with parts broken away and shown in section, and showing thecarburetors on the engine;

Fig. 3 is a wiring diagram;

Fig. 4 is a view in elevation of a switch unit of the choke system;

Fig. 5 is a side elevation of Fig. 4;

Fig. 6 is a plan view of one of the carburetors on the engine;

Fig. 7 is an end view of the carburetors as viewed from the right ofFig. 6;

Fig. 8 is a vertical section taken on line 8-8 of Fig. 6;

Fig. 9 is a vertical section taken on line 99 of Fig. 6;

Fig. 10 is a vertical section taken on line 1010 of Fig. 6;

Fig. 11 is an end view of the carburetor as viewed from the left of Fig.6, with parts broken away and shown in section;

Fig. 12 is a detail section of the carburetor; and,

Fig. 13 is a view similar to Fig. 5, on a reduced scale, illustrating amodification of the switch unit.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring to Figs. 1 and 2 of the drawings, there is 'indicated at 1 anoutboard motor. The shroud of the outboard motor is shown as removed sothat the engine 3 is visible. As herein illustrated, this engine 3 is athree cylinder engine, and three carburetors 5, 7 and 9 are provided onthe engine, one for each cylinder. A starting motor for the engine isindicated at 11. A generator driven by the engine is indicated at 13.

Carburetors 5, 7 and 9 are .horizontal or side carburetors, arranged oneabove another. They are identical and a description of one will suificefor all. Each of the carburetors (see Figs. 6l2) comprises a body 15formed to provide a horizontal mixture conduit 17. This is open at bothends. It has a restriction 19 (see Fig. 8) intermediate its ends so thatit constitutes a venturi. At the outlet end of the mixture conduit, thebody 15 has a flange 21 for attachment of the carburetor to the engine.A throttle shaft 23 extends vertically across the mixture conduitadjacent its outlet end and carries a throttle valve 25. A choke shaft27 extends horizontally across the mixture conduit adjacent its inletend and carries a choke valve 29.

Extending down from the body 15 is a tubular stem 31. A fuel bowl 33 hasits bottom 35 engaging the lower end of the stem 31 and its rim engagingthe bottom of the body 15. A screw 37 extends through a hole 39 in thebottom 35 of the bowl and is threaded in the lower end of the stem 31 tohold the bowl in place. The body 15 is formed with a fuel inlet 41 forreceiving fuel from a supply. Extending down into the bowl from theinner end of this inlet is a needle valve 43 controlled by float 45 on afloat arm 47 pivoted at 49. Float 45 is of annular form surrounding stem31. The arrangement is :such as to maintain a substantially constantpredetermined level of fuel in the bowl. A bowl vent isindicated at 51.

A main fuel nozzle 53 has its lower end 55 threaded in the stem 31. Theupper end of this nozzle projects upward into the mixture conduit 17.Nozzle 53 has an external flange 57 engaging a shoulder 59 at the upperend of the stem 31. From its lower end 55 to the flange 57, the nozzleis of smaller external diameter than the internal diameter of the stemso as to provide an annular space 61 around the nozzle. This space is incommunication with the outside atmosphere via a passage 63 (see Fig. 9).The nozzle 53 has a plurality of perforations therein such as indicatedat 65. Fuelis adapted to enter the stem 31 above the screw 37 and belowthe lower-end of the nozzle through a port 67 under control of anadjustable needle valve 69.

An idle tube 71 has an enlarged upper end 73 fixed in a hole 75 in thetop of the body 15 and extends down across the mixture conduit 17 anddown through the nozzle 53 concentrically within the latter. Body 15 isformed to provide an idle passage 77 vfromhole 75 to an idle port 79v(see Fig. 12) opening into themixture conduit 17. An idle adjustingscrew is indicated at .81.

A throttle arm *83 is secured on the throttle shaft 23 at its upper end.A spring for biasing the throttle valve 25 closed is indicated at 85. Anarm 87 is fixed on one end of the choke shaft 27. A'spring for biasingthe choke valve 29 open is indicated at 89.

In accordance with this invention, and as illustrated in Fig. 1, thechoke shaft arms 87 of the three carburetors 5, 7 and 9 are linkedtogether by a vertically extending link 91. A solenoid 93 is mounted invertical position on the engine 3 adjacent the link. The solenoid has aplunger 95 which has its lower end connected as indicated at 97 to alever 99 pivoted at 101 on the engine 3 having a connection as indicatedat 103 with the link 91. The arrangement is such that .when the solenoidis deenergized, the choke springs 89 of the three carburetors hold thechoke valves of all three carburetors in their fully open position(horizontal) with the lever 99 and the plunger in a lowered retractedposition. When the sole noid is energized, the plunger moves upward toswing the lever 99 upward and drive the link 91 upward ,to move thechoke valves in closingdirection. How far the choke valves are moveddepends on the voltage applied to ,the solenoid in relation to theclosing bias of the choke springs; the higher the voltage, the more thechoke ,valves move.

Referring now to Fig. '3, the system is shown to comprise afirst circuitC1 including a starter switch 105 and afirst engine temperatureresponsive switch 107 for establishing suflicient'voltage across thesolenoid 93 to hold the chokevalves 29 fully closed against theopening-bias of springs 89. This first circuit includes a line 109connected to one terminalof a battery B extending to the starter switch105 (the other terminal of the battery being connected to ground asindicated at 111), and a line 113 extending from the starter switch to107, with a line 115 extending from switch 107 to one terminal of thesolenoid, and a line 117 extending from the other terminal of thesolenoid to ground. Starter motor 11 is connected in a line 119extending from line 113 to ground. The system also comprises a secondcircuit C2 including an ignition switch 121, 'a resistor 123, and asecond engine temperature responsive switch for establishing a lowervoltage across the solenoid sufficient to 'hold the choke valves 29 onlypartly closed (partly open) against the opening bias of springs 89. Thissecond circuit C2 includes a line 127 extending from line '109 to theignition switch 121,-a line 129 extending from the ignition switch tothe resistor 123, and a line 131 extending from the resistor to theswitch 125, and is completed-by lines 115 and 117. Line 115 is connectedto a conductor 133 which connects switches 107 and 125. The ignitioncircuit is indicated at 135 extending from line 129.

The temperature responsive switches 107 and .125 are combined in a-unitshown in Figs. 1, 3, 4 and 5 and designated in :its entirety by thereference character 137. This .unit comprises a rectangular insulationbase 139. A pair ofterminal screws 141 and 143 are threaded in the baseat one .end thereof, these screws being located sideeby-side. Screw 141is a terminal of .the first switch .107. Screw 2143 is a terminal of thesecond switch 125. At its other end, the-baseis formed with a ledge 145.A pair elf-electrically conductive leaf springs 147 and 1-49.extendfrom-the ledge over the screws. Each ofthese springscarriesacontact suchas indicated at 151 at its freeend engageable with a contact ,153 on theend of the respective screw. The leaf springs are clamped on the ledgebymeans of a .conductivebar which constitutes the previouslymentioned-conductor 133, this bar 133 being secured to the base-by abolt .155 which constitutes a common terminal for the two switches.

Switch-107,comprises the leaf spring .147 and a therrnostatic.blade*157underlying this leaf spring foractuating it. Switch 125 comprises theleaf spring 149 and a thermostatic blade 159 underlying this leaf springfor actuating it. Each thermostatic blade has one end fixed on a spacerblock 161 by means of a bolt 163 and a finger 165 at its other and freeend engaging the respective leaf spring. Blades 157 and 159 are arrangedto bend away from the base 139 on heating to bend the leaf springs 147and 149 outward away from the base and disengage the contacts 151 on theleaf springs from the contacts 153 on the terminal screws 141 and 143.Blade 157 of switch 107 is adapted to open leaf spring 147 of switch 107at a lower temperature than that at which blade 159 of switch 125 isadapted to open leaf spring 149 of switch 125. The switch unit 137 ismounted on the exhaust manifold of the engine 3 in a position such asillustrated in Fig. 1. Line 113 is connected to screw 141. Line 131 isconnected to screw 143. Line 115 is connected to bolt 155.

Operation is as follows:

Battery B may be a twelve volt battery, for example. Thermostatic blade157 of switch 107 may be selected so that switch 107 opens at about 90F., for example. Thermostatic blade 159 of switch 125 may be selected sothat switch 125 opens at about 105 F., for example. Accordingly, whenthe engine temperature is relatively low so that switch 107 is below 90F., and the starter switch 105 and ignition switch 121 are closed tostart the engine, approximately twelve volts is applied to the solenoid93 via circuit C1, and this is suflicient to move the choke valves 29 ofall three carburetors 5, 7 and 9 to their fully closed position againstthe opening bias of the choke springs 89. In this respect, it will beobserved that with switches 105 and 107 closed, circuit C1 shunts theresistor 123 to apply full voltage to the solenoid.

As soon as the engine has started, the starter switch 105 is opened, butthe ignition switch 121 remains closed. Accordingly, current is suppliedto the solenoid 93 from the battery B through the circuit C2 includingresistor 123 and switch 125. The resistor 123 drops the voltage to avalue less than the twelve volts of the battery voltage, for example tosix volts. With six volts applied to the solenoid 93, the solenoid isactuated only partly to close the choke valves 29 of the threecarburetors 5, 7 and 9, closing these valves about halfway against theopening bias of the choke springs 89. The choke valves remain in thishalf closed (half opened) position until the engine temperature hasincreased to the point where switch 125 reaches its 105 F. openingtemperature. Thereupon the switch 125 opens to deenergize the solenoid93, and the choke valves 29 are then swung to their fully open positionby the choke springs 89.

If the engine should be at such a temperature when the starter switch105 is closed that the switch unit 137 is at a temperature between 90 F.and 105 F., meaning that switch 107 is open and switch 125 is closed,then when the starter switch 105 is closed, six volts will be applied tothe solenoid 93 via circuit C2. This will result in partial closing ofthe choke valves on starting instead of full closing of the choke valvesas occurs in starting the engine cold. As above, when the engine warmsup, switch 125 opens to deenergize the solenoid, and the choke valves 29will then swing from their partly opened position to their fully openposition under the bias of the choke springs 89. If the engine should beat a temperature such that the switch unit 137 is at a temperature over105 F. when the starter switch 105 is closed, both switches 107 and 125will be open, and closing the starter switch 105 will not result in anyoperation of the solenoid. Accordingly, under these conditions, startingis efiected with the choke valves fully opened.

thermostatic blade 157a for switch 107 and clamping its end on ledge 145under an electrically conductive memher 171 for connecting the blade157a in shunt around the leaf spring 147 so that it carries current whenthe leaf spring 147 is closed. Then, when starter switch is closed,blade 157a is self-heated, this heating being relatively slow. If theengine starts quickly, the operation is the same as previouslydescribed. If the engine should not start within the prolonged time(five to ten seconds, for example) it takes the blade 157a to heat up tothe point where it opens the leaf spring 147, then, even though theengine is cold, switch 107 opens so that the choke valves 29 are openedby the springs 89.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

We claim:

1. In a fuel system for an internal combustion engine, a carburetorhaving a mixture conduit, a choke valve in said conduit, means biasingsaid choke valve to its open position, a solenoid operable to move saidchoke valve toward its closed position, a source of current, a firstelectrical circuit leading from said source of current to said solenoid,an engine starter switch and a first engine temperature responsiveswitch in said first circuit operable to energize said solenoid to movesaid choke valve to its closed position, a second electrical circuitleading from said source of current to said solenoid, an engine ignitionswitch, an electrical resistance coil, and a second engine temperatureresponsive switch in said second circuit operable to energize saidsolenoid to move said choke valve to its partly closed position, saidfirst and second temperature responsive switches being initially inclosed position, and each being movable to its open position responsiveto an increase in temperature, said first temperature responsive switchbeing operable at a relatively lower temperature than said secondswitch.

2. A fuel system according to claim 1 wherein each of said temperatureresponsive switches comprises a contact carrying spring member, and athermostatic element to actuate said spring member.

3. A fuel system according to claim 2 wherein the thermostatic elementof said first temperature responsive switch is connected in said firstcircuit to be heated by current passing therethrough.

Sisson June 6, 1933 Hunt May 16, 1939

